On the System Status page, the fault tolerant Data Aggregators could have a status of:

Active: Up and in useInactive: In standby modeMaintenance: Administratively down, not running and will not be failed over toFailed: Down or cannot be contacted. and not in Maintenance

When configured for Fault Tolerance, you stop/start the DA as follows:

1) Stop:

a) RHEL 6.x:

service dadaemon maintenance

b) RHEL 7.x, SLES, or OL:

DA_Install_Directory/scripts/dadaemon maintenance

2) Start:

a) RHEL 6.x:

service dadaemon activate

b) RHEL 7.x, SLES, or OL:

DA_Install_Directory/scripts/dadaemon activate

In a fault tolerant environment, when the Primary is up and the secondary is available for failover you will seethe two DAs on the status page as Active (primary running DA) and Inactive (secondary DA ready for fail-over)

To fail the active over to the inactive DA, on the active DA, run the command above to put it into Maintenance mode

After some time, the inactive DA will become Active.Then you can activate the DA that was put into maintenance mode as noted above.As there is a running DA, the DA will not start on that server, but it will be available to be failed over to.

To fail back, perform the procedure above on the now active/inactive DAs